期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2003
卷号：100
期号：18
页码：10219-10224
DOI：10.1073/pnas.1737042100
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Metabotropic glutamate receptors (mGluRs) are responsible for the effects of glutamate in slow synaptic transmission, and are implicated in the regulation of many processes in the CNS. Recently, we have reported the expression and purification of a mGluR from Drosophila melanogaster (DmGluRA), a homologue of mammalian group II mGluRs. We have shown that ligand binding to reconstituted DmGluRA requires the presence of ergosterol in the liposomes [Eroglu, C., Cronet, P., Panneels, V., Beaufils, P. & Sinning, I. (2002) EMBO Rep. 3, 491-496]. Here we demonstrate that the receptor exists in different affinity states for glutamate, depending on the membrane composition. The receptor is in a high-affinity state when associated with sterol-rich lipid microdomains (rafts), and in a low-affinity state out of rafts. Enrichment of the membranes with cholesterol shifts the receptor into the high-affinity state, and induces its association with rafts. The receptor was crosslinked to photocholesterol. Our data suggest that sterol-rich lipid rafts act as positive allosteric regulators of DmGluRA.
关键词：cholesterol ; metabotropic glutamate receptor ; nano-electrospray ionization tandem MS ; regulation of G protein-coupled receptors
